Jeppesen Oral- Chapter 3 (Turbine Engine)

Answer 1

With higher bypass, provides more thrust for same or even lower fuel consumption

Answer 2

Air inlet, compressor section, combustion section, turbine section, exhaust section, gearbox

Answer 3

Forward speed, compressor speed and density

Answer 4

Axial and centrifugal

Answer 5

Dove tail Fir-tree Bulb type

Answer 6

Two intra-rotating compressor sections

Answer 7

Can type, can-annular, annular, reverse-flow annular

Answer 8

Cooling air along inside of the liner

Answer 9

Flame propagation

Answer 10

They direct mass flow to drive the turbine rotor at a specific angle

Answer 11

By directing bleed air onto the face of the disc or by grooves cut in the disk

Answer 12

They are used as oil seals for the rotor shaft bearings

Answer 13

It is induction of the torque developed by a turboprop or turbo-shaft engine

Answer 14

Small power turbine, compressor and electrical starter

Answer 15

When it is supplying bleed air

Answer 16

With its own electrical starter and battery power

Answer 17

Typically the left main tank

Answer 18

At or near its rated speed. APU fuel control automatically adjusts the fuel flow to maintain rated speed

Answer 19

A load control valve modulates the pneumatic load to maintain the EGT within limits

Answer 20

First bleed air valve is closed, then it is run for a specific amount of time to allow EGT to stabilize. If suddenly shut down without cooling period, thermal shock and damage can occur

Answer 21

3 minutes

Answer 22

Fuel pressure

Answer 23

Overlapping of the mid-span shrouds of the fan blade

Answer 24

Any rubbing sound or unusual sounds from within the engine

Question 25

What is the purpose of the stators in an axial-flow compressor?

Answer 25

The stators convert some velocity energy into pressure energy and change the direction of the air so it is proper for the next stage of rotors.

Question 26

How many igniters are there normally in an aircraft turbine engine?

Answer 26

2

Question 27

What is the main purpose of the turbine nozzle in an aircraft turbine engine?

Answer 27

The turbine nozzle directs the hot gasses as they leave the combustors so they will turn the turbine wheel with maximum efficiency.

Question 28

What is meant by a free-turbine turboshaft engine?

Answer 28

A turbosaft engine that has a turbine wheel or stage of turbine wheels that is not used to drive the compressor of the gas generator section of the engine. This free turning drives the propeller in a turboprop engine or the transmission and rotor of a helicopter.

Question 29

Why do some axial-flow turbine engines have more than one set of turbines and compressors?

Answer 29

A two-spool turbine engine has a low-pressure and a high-pressure compressor, each driven by its own turbine. The two independent systems operate at the speed at which they are most efficient.

Question 30

What kind of bearings are used to support the rotor shaft of an aircraft turbine engine?

Answer 30

Antifriction bearings, such as ball bearings or roller bearings.

Question 31

What is meant by a turbofan engine?

Answer 31

An axial-flow turbine engine in which the first-stage compressor blades are lengthened,so they can force air around the outside of the gas generator portion of the engine.

Question 32

Why is it important that a turbojet engine be allowed to cool before it is shut down after it has been operated at a high power setting?

Answer 32

If the engine is shut down while it is hot, there is a possibility that the shroud will contract around the turbine wheel and seize the rotor.

Question 33

What is meant by a hung start in a turbine engine?

Answer 33

A start in which ignition occurs, but the engine does not accelerate to a self-sustaining speed.